(a) Field of the Invention
The present invention relates to an automatic switching means for microscope illumination system which functions to automatically set up an illuminating condition optimum for the magnification level of an objective lens to be used for microscopy when objective lenses are switched from one to another having a different magnification level.
(b) Description of the Prior Art
It is generally necessary to switch an illumination system to another assuring an illuminating condition matched with an objective lens to be used for microscopy when objective lenses are switched from one to another having different magnification level in a microscope. For this purpose, an illumination system for microscopes usually comprises plural number of different condenser lenses which are to be selected for use in conjunction with switching of objective lenses, and a removably arranged auxiliary lens which is to be inserted and removed into and from the optical path of the illumination system, thereby setting up an illuminating condition optimum for an objective lens to be used for microscopy.
In case of an illumination system for microscopes which is so adapted as to set up an illuminating condition optimum for an objective lens to be used for microscopy when objective lenses are switched as described above in a microscope, it is very convenient to devise the illumination system so as to be automatically switched in conjunction with switching of the objective lenses in the microscope, and there have already known microscopes equipped with illumination systems which are automatically switchable as described above. A first type of such automatic switching means comprises a means for detecting an objective lens used in the revolver of a microscope and is so devised as to detect what objective lens is selected for microscopy to determine position of the revolver on the basis of the signal detected by said detecting means, thereby switching the illumination system. A second type of automatic switching means for microscope illumination system is equipped with an interlocking mechanism which automatically switches an illumination system in conjunction with switching of the revolver of a microscope. Further, there is known another automatic switching means, of a type similar to said first type, which comprises signal members arranged on the sides of the revolver and is so devised as to automatically switch an illumination system on the basis of signals obtained with the signal members.
Since all of these automatic switching means are so designed as to detect magnification levels of objective lenses in conjunction with rotation of the revolver, it is essential that correct correspondence is established between objective lenses and tapped holes formed in the revolver for setting the objective lenses. In other words, such switching means require setting objective lenses correctly in the corresponding holes, thereby making setting works rather tedious. Should the objective lenses be set in wrong holes, it may be impossible to set up illuminating condition optimum for an objective lens system to be used for microscopy.